Rope knife



F. J. SPANG ROPE KNIFE July 12, 1932.

Filed Feb. 3, 1931 2 Sheets-Sheet 1 INVENTOR ATTORNEY F. J. SPANG ROPE KNIFE July 12, 1932.

Filed Feb. 3, 1931 2 Sheets-Sheet 2 IN V ENTOR.

' ATTORNEY Patented July 12, 1932 Application filed February 3, 1931. SeriaINoI 513339;:

My invention relates to rope knives of the character employed in connection withwell drilling apparatus, as-for example, when severing the cable or rope from a string of tools 5 stuck in an oil or gas well prior to withdrawal thereof by means of a fishing tool. f

The present improvement 1s particularly directed to an Lip-cutting rope knife wherein the cutting motion is provided by repeated 1 upward strokes or jars of the kn fe, whereby the cutter is forced through the rope to be cut,

although it is'to-be understood that my invention is not limited thereto. 1

An object of this invention is to provide a knife body having a cutter operably disposed therein, a rope-receiving slot or opening in the body, and a removable key or closure" member therefor, said key or closure mem-Z her-constituting an anvil for the cutter.

A further object is" to provide'me'ans for normally retaining the cutter out of engagement with the rope and guided tripmeans for releasing said cutter for engagement with the rope.

- Additional 'objectsand advantages willbecome apparent from the following descrip 1 tion taken inconne-ction with the accompany ing drawings, wherein:

Fig. 1 is a front elevation of a'rope knife embodying my invention; 7 g

V Fig. 2, a side elevation thereof; Fig.. 3, a bottom'pl'an view;

Figs, a longitudinal sectional view taken on the line IV-+117 of Fig. 1; Q

Fig. 5, a cross sectinbn the line Va-V i lL 1 i Fig.- 6, across section onthe line ofFig.2; l p m Fig. 7, an enlarged perspective viewof the trip and itsv guide; and

Fig. .8,- a perspective, vlew ofgthe trip pin.

Referring to the drawings,;A designates generally the knife body, preferably formed .111.; of bit steel and having an especially hardened lower portion or cylindrical body 2. As illustrated and as preferred, the body A,

in addition to the cylindrical portion 2, in

cludes an upwardly extending tapered shank- 5'333 or stem 3 and a taper-threaded portion 4;

adapted to be coupled with means for lower ing the knife intothe'well. 5-

Thecylindrical body 2 is' formed rwith a longitudinally extending rope-receiving .mbmmmam; 9 u n-EB: P NNSX AN f 1.5

opening or slot 5,adapted to receive the rope,

or cable. 6, said rope being "retained therein by means of aslidably"mounted removable verse cotter pin'orbolt 12 is passed through 1 anopening in member"? and through the walls of thebody'2 to retainlmember7 in" place. Member? is made ofhardenedisteel, and cooperates with the cutting blade in the operation of severing the r0pe,as more fully I hereinafter referred-t0.

Disposed rearwardly of the openingorslotj 5, and in alinement therewith, is an irregu larly-shaped chamber or T-shaped recess 13 5' designed to receive the-cutter andpartsof coacting mechanism. This chamber has a rear wall 14 inclined downwardlyfand for wardly, and has" longitudinal grooves 15 formed adjacent said rearwall 14.' A rope 1 cutter or knifeblade 16 is positioned on and movable. with respect to the said. inclined wall 14. and is retained thereon by means of longitudinaltongues 17 at thefirear edges of the cutter, enteredvinto' saidgrorives. The I cutter 16 iseprovid'ed withaforwardly ex-r' tendingv sharpened cuttingiedge portion 18,-. I normally maintained out of engagement with the rope 6 by means of a transversetrip pin 7 19, and against the action of a spring 20, said spring being secured inra suitablerecess 21:? above the chamber 13'by means of a screw22i Thus, it will be seen that when the knife-iis assembled inthis manner about the rope or:

cable fi; upon efiecting a release of-th'evcutter 1-6,-rep'eated upward strokes or jars of the" knife .body A'will force-.the. said cutter throughtherope, due to the action ofTthe' c d: M111 reo iS t be noted:- hat; thi cu t ng a t n a e aplaee against.

leg

the closure member 7, and that said member functions as an anvil for the cutter, and pro- Vides a solid cutting surface for the latter.

' 7 Since the member 7 is removable, it may be readily renewed when it becomes damaged through use. a

For the purpose of releasing the cutter 16, I provide trip-means, generally designated B. These means are associated with and cooperate withthe trip pin 19, V The trip mechanism' as showncomprises a bifurcated trip'or "contact'plate 23 disposed below the body 2 and normally spaced therefrom.

Secured to the plate 23in any suitable man ner, and extending upwardlytherefrom in spaced relationship, are a combined trip and guide rod'24 and a guide rod 25, said "rods be-' ing respectively slidable in 2a formed in the body 2.

posed in thehguide rodopening25a contacts with the said rod tonormally maintain the openings 24a and trip plate'23 spaced from the body. The

movement of the trip mechanism is: limited by means of a. vertical slot 27 "in the trip rod 24.and a pin or bolt 28 in the bodyr2, hav ing an'end thereof entered inthe slot. The bolt 28 also functions to. prevent the trip dropping free of the knife; f 4

The trip pin 19 is disposed in a transverse opening 29, formed in'the body 2,"and extends V at right angles to and intersectswith the trip rod opening 24. Q Said trip pin is cut away at 30', and isformed with aninclined shoulder or abutment 31. ,Theupp'er end of the trip rod-24 is also cut away, as'at 32, to form a similarly inclined shoulderor wedge portion- 33, the latter being adapted to be entered into the cut-away'portion 30 of the trip pin 19, in the manner shown in Fig. 1. 3 When the .trip pl'ate:23 is" in the loweredposition as shown, "only-the point-of the wedge por-,- tion 33 willabe entered into the, trip pin por-w tion 30, thercbypermitting the pin-to project inwardly, as at 34, to engage the cutter 16 and retain it'. in its retracted position. p

However,'when the knife islowered on the I rope 6,'the trip plate 23 will engage the rope socket or upper portion 35 of the string of" tools to which said rope is attached, and a continued downward motion of'the knife will cause the wedge portion 33'of rod 24 tolbe moved upwardly in contact with the inclined V abutment 31 on the trip" pin to retractthe same into its opening 29, thereby permitting thecutter l6 to-fall into engagement with the rope and, upon repeated upward strokes f for thetripping face. I The direction 'ofm vea mentissuc'h that no binding and the ofthe knife, beforced through said rope;

fIt -will be noted that'the trip mechanism is inserted in thebody parallel t'othe' axis of the tool" and "is of substantial size,-an d that aguide,.in addition to the trip rod, maybe employed, thus providing" considerable support spr'ingi26 functionsfto insure the positioning spring 26 disof the tripping rod to receive the knife lock 19 without preparation of the operator.

I claim:

1. In a rope knife, a single circular body having a rope-receiving slot therein, a cutter movable in the body, a slidably removable closure member for the. rope-receiving slot, said closureinember constituting'ananvil for the cutt er,otrip means for tlfe cutter, said means including a transversely movable trip i pin normallyengagingthe cutter, a trip rod disposed and movable parallel to the axis of the" body for retracting the trip pin, a trip plate, and a guide rod for the trlp plate movable parallel to the'axis of the body.

2. In a rope knife, a body having rope re ceiving and retainingmeans therein, acutter movable in thebody, a transversely movable rod disposed and movable parallelto the axis of the body, for retracting the trip'pin, a

V trip pininormally engaging the cutter,-a trip trip plate, and a guide rod for the trip plate 7 movable parallel to the axis of the body.

, 3. In. a rope knife, a body having ropesre-y. ceiving and retaining meansithe'reon, a cutter movablein the body, a transversely movable trip pin normally engaging the cutter, a trip plate having a guide rod, a triprod disposed and movable parallel to the axis ofthe body, an inclined abutment'on the trip pin, and awedge portion on the trip rod engagingthe said abutment for retracting thetrip PHL; V v I c 4.7.111 a r pe ni cyl ndr ca sl d body having longitudinally extending grooves therein, a cutter movable in the body, a closure 7 member removably positioned-in the body and av g p oje ng Port on hereon for en: gaging said grooves, a head portionon said me b r or e gag ng a shoul er t e ody,

means fo lcck ng t e c osur m mbe -the y, means fo re a n ngthe cu e in e tracted position, and trip means for releasing" hecu' ter i ga rip 1 d ispos -and o x of the cdyi ret act ng t e ari e a' tr'ipip'la te, a vertically momma guide rod for the trip plate,and a spring'forthe'guide rod movableiparall'el to the axis ofthe body. In testimony whereof I aflix'mylsignature.

'- F RD NANPL KJSPANG' 

